1. Field of the Invention
The present invention is related to motors which utilize the force of gravity to impart a rotational torque on a rotor and, more particularly, is directed toward a gravity actuated motor of the type described which utilizes as an actuating means the selective expansion and contraction of a vapor from a sealed volatile fluid medium.
2. Description of the Prior Art
The prior art is replete with devices known generally as gravity actuated motors which take advantage of the force of gravity to produce a rotational torque on a rotor. Generally speaking, some means are provided for producing a weight imbalance either in or about the rotor to provide the rotary motion. Such means have been known to take various forms including electrical, mechanical, hydraulic, thermochemical, or the like. Generally speaking, however, such devices have been unduly complex, expensive to produce, mechanically unreliable, inefficient in operation, and prone to mechanical breakdown.
An example of a typical prior art rotary gravity motor is set forth in the U.S. Pat. No. 3,941,030 to Massung in which he utilizes fluid pressure as the means for creating the weight imbalance. More particularly, Massung provides a rotor having a plurality of flexible cells which are arranged in diametrically opposing pairs which are in fluid communication with one another. Each pair of cells contains an amount of liquid sufficient to fill one cell. Fluid pressure is controllably applied to the collapsible cells to force the liquid in the lower cells to their paired counterparts in the upper portion of the rotor to produce the desired torque.
Another type of rotary gravity motor is exemplified by U.S. Pat. No. 3,659,416 to Brown in which a pair of chambers on opposite extremeties of a rotor are in fluid communication with one another through a diametrically extending hollow spoke. The chambers contain an amount of volatile liquid and an electrically-actuated heating element for vaporizing the liquid to force same to move from a lower to an upper chamber to impart the desired torque on the rotor.
Yet another type of rotary gravity motor is illustrated in U.S. Pat. No. 2,513,692 to Tubbs who illustrates a plurality of rotating expansion chambers which are successively dipped into a hot water tank. Each expansion chamber contains a volatile liquid which vaporizes when its associated chamber is immersed in the hot water tank. The vapor causes the chamber in turn to expand, which motion is translated via mechanical linkages to a rotary output motion.
Each of the devices set forth in the foregoing patents is believed deficient in one or more respects which has hindered their widespread adoption and use. For example, the Massung device requires extensive fluid pressure valving and control mechanisms, the Brown device requires electrical energy and heating elements for operation, and the Tubbs structure is dependent upon intricate and maintenance-prone mechanical linkages which also tend to act as an inefficient means for transferring the generated power.
Other U.S. Pat. Nos. of which I am aware which are related to this general art area include: 2,475,343; 2,597,890; 2,601,600; 2,755,619; 3,441,482; and 3,785,144.